Which of the following sentences is true?
Select one:
a. If a bacterium's cell volume decreases after being placed in solution A, then solution A is thermotonic relative to the bacterium.
b. If a bacterium's cell volume decreases after being placed in solution A, then solution A is hypertonic relative to the bacterium.
c. If a bacterium's cell volume decreases after being placed in solution A, then solution A is hypotonic relative to the bacterium.
d. If a bacterium's cell volume decreases after being placed in solution A, then solution A is isotonic relative to the bacterium.